Automatic aerial photography system



July 21, 1959 s. w. GODDARD AUTOMATIC AERIAL PHOTOGRAPHY SYSTEM 2 SheetS-Sheet' 1 Filed Feb. 1956 i INVENTOR. I 07,, 1/. 531/1471 Jul 21; 1959'G. W GODDARD AUTOMATIC AERIAL. PHOTOGRAPHY SYSTEM Filed Feb. 9, 1956 2Sheets-Sheet 2 N INVENTOR.

4m, fm ar/ BY W ATTORNEYS backs.

to. produce long shadows.

AUTOMATIC AERIAL PHOTOGRAPHY SYSTEM :George W. Goddard, Chevy Chase,Md., assignor to Bulova Research and Development Laboratories, Inc,Woodside, N.Y., a corporation of New York Application February 9, 1956,Serial No. 564,535

' 4 Claims. eras-12.5

The present invention relates generally to "aerial photography and'more'particularly to techniques and apparatus for automatically takingaerialphotographs under conditions requiring artificial illumination.The invention is applicable not only to'pilot-operated reconnaissanceplanes or missiles, but also to remote-controlled or pilotless aircraft.7

Aerial night photography entails the use of brilliant flashes for theeffective illumination of the terrain being photographed. For thispurpose it has heretofore been the practice to eject a flashlightexplosive bomb from the rear of the plane and to provide a camera havinga shutter mechanism which is actuated by a light-sensitive cellresponsive to the light emitted from the flashlight. Thus the instantthe'bomb explodes, the shutter is caused to open for a brief intervaland the photograph is taken at the point of maximum illumination. For amore detailed description of'such systems, reference is made to theearlier patent to Goddard 1,936,595.

In aerial reconnaissance operations forthe purpose of photographingmilitary ground equipment and personnel, the conventional photographicsystem has certain draw- To facilitate the identification of objectsprojecting upwardly from the ground, it is desirable that the angle ofillumination be such as to produce distinct and relatively-long shadows.Obviously, where the source of illumination is in close proximity to thecamera, then little shadow will appear in the photograph 'and diflicultywill be experienced in distinguishing objects therein.

'Inthe conventional aerial photographic system, the'camera plane andlong shadows are not .developed in the photograph.

It is desirable for eflectivereconnaissance photography P- that theflareexplosion take" place 'well to the rear. of

the plane but at the same time "it is important that the altitude of theexplosion be not too far below that'of the plane. In this -way theilluminating rays will be and the angle of illumination willbesufliciently oblique :This I optimum relationship between the positionof the flare with respect to the plane and the terrain cannot beattained with known systems, particularly when the plane is flying atlow altitudes.

Accordingly, it is the principal object of the invention to provide anaerial photographic system in which a flash powder cartridge receivessuflicient rearward propulsion to place the flash far enough rearwardsof the vehicle to produce long shadows in the photograph.

More particularly, it is an object of the invention to provide a systemof the above type wherein the exhaust of a jet or rocket propelledmissile acts to ignite and to project a flash powder cartridgerearwardly at ahigh velocity.

United States Patent properly distribnted,..oyer the regionbeingphotographed Also, an'object of my invention is to provide a flashpowder cartridge having igniter means adapted to operate when thecartridge is-thrust into the flame exhaust of a plane, the igniter beingtied to a powder mass by a fuse whereby the cartridge is caused toexplode after a predetermined interval.

Still another object of the invention is to provide a flash cartridgedispensing and'ignition system synchronized with single or multi-cameraoperation at high speed.

Briefly stated, in a reconnaissance system for night photography inaccordance with the invention, the vehicle, employed is of theconventional jet or rocket' type in which the fuel gases are expelledfrom an exhaust at the rear of the vehicle. Each vehicle carries aconsiderable number of flash cartridges depending uponthe size of thevehicle and the number of aerial photographs to be taken. Thecartridges,'made in any shape or size, are ejected from a dispenser downa chute into the flame of theengine exhaust position. The rate at whichthe cartridges are dropped-into the flame may be predetermined inaccordance with the speed of thevehicle, the altitude and amount ofoverlap 'desired 'in the strip of aerial photographs. Each cartridgeincludes a multiple of flame igniters and fuses on each side of thecartridge to insure immediate ignition on contact with the flame. At'this'instant, the cartridge is subjected to a propulsive force ejectingit rearwardly. The cartridge is exploded at a distance in the rear ofthe vehicle determined by the fuse burning time, the resultant flashbeing far enough rearward to produce long shadows in the photograph. v I

Fora better understanding of the invention as well as other objects andfurtherfeatures thereof, reference is had'to the following detaileddescription to be read in conjunction with the accompanying drawing,wherein like components in the various views are identified by likereference numerals.

In the drawing: Figure '1 is a diagrammatic view of 'an automatic aerialphotographic system in accordance with the invention installed in aplane drone or missile.

Figure 2 is a separate viewof the flashlight cartridge. Figure Sisaschematic 'view of the camera and control apparatus as 'well as the'cartridge dispenser.

Referring now' to the drawing and more. particularly to Figs. *1 and-3,a typical jet or rocketpropelledplane is designated by-thenumerallO. Anaerial camera 11 is mounted in the fuselage 0f the plane and is orientedto take vertical photographs of the terrain lying below the plane. "Thecamera may be of a type adapted 'to take strip pictures and includes'ashutter mechanism 12 which may be of any standard design actuated by alever 13. Mechanicallycoupled to lever 13 is an electromagnetic device14 which when energized acts to'actuate the lever, therebybp'erating theshutter.

An ele'ctronic control circuit '15 functionstofcontrol device, thecircuit including a photocell 16. 'Cell 16 is preferably mounted attheend of a tubular shield '17 projecting from the fuselage of theplaneat'an 'ang'lesuch that the cell proper will be screened from lightemanating from the aircraft and from the ground directly below thelatter. Consequently, light will not impinge on the photocell 16 unlessthe source thereof is located well to the rear of the plane and in linewith the shield. ,This will insure against accidental operation of thecamera shutter by light coming from sources other than the flare.

Photocell 16 is connected to the input of an amplifier 18 of anysuitable design, the output of the amplifier being connected to theelectromagnetic device 14. In

operation, the camera 11 normally has its shutter closed andset forinstantaneous exposure at the appropriate moment. A flash cartridge 19is released astern and after 1 a predetermined interval determined 1 bythe 1 fuse char- 1 1 1 1 rairu Light from the exploding flare isdetected by the 1 acteristics, the cartridge explodes to illuminate theter- 1 .photocellrto produce a voltage which when: amplified has 1 1 1 amagnitude sufiicient' to energize electromagnetic device 1 4, therebyoperating theshutter so as to make an installqtaneous exposureofthe filmin the camera. The control intensity curve-oi: the flash so asto operatethe "shutter 1 1 1 I only when the illumination attains itspeak-intensity; 1

I 1 1 1 1 Cartridge 19, as shown separately inFig. 12, is made in 1 1 1any1size or shape, and includes a frangible casing 1 1 which contains amass or charge of flash powder 21 which A 1 may1be of astandardAirForcehigh efliciency type; 1 The 1 11 11 I 1 charge 21 is adapted toburst'the: casing when exploded 1 1 :provided at either end of thecasing an igniter 22 in the 1 1 1 ,form ;of a container of black powder,Projecting extennally front the igniters are 1a plurality of use 'hairs23 powder at a point sufficiently. rearward of themissile to 1; In ajetor rocket propelled missile provided with 1 1 1 rear exhaust tubesthrough which propulsive gases are. 1 1 emitted, an aerial photographicsystem comprising a 1 1 1 1 1 camera having an exposure shutter, meansto drop a flash 1 1 "powder cartridge into said exhaust to causerearward 1 1 1 propulsion thereof, said cartridge having fuse means ig-11 1 1 1 1 1 1 I nited by said gases to effect an explosion of the dash 11 1 1 1 circuit is preferably 1 adjusted with respect to the light 1produce long: shadows, and means responsive -to the 1 1 1 1 1illumination of said flash powder- 1:0 actuate said shutter; 1 i 1 2; Anaerial photographic system for a jetor rocket 1 1 1 plane having anexhaust tube, said system comprising a 1 1 1 1 1 camera positioned inthe fuselage of the plane anddi- 1 1 1 4 rooted to photograph theterrain beneath'thepl'ane, said 1 camera including ashutter mechanism, alight-responsive 1 1 1 1 1 1 electronic control system coupled tosaidshutter mecha-i 1 1 ni-sm for actuating same, and means to release aflashis projected rearwardly of'the plane, saidcartridge having 1 1 1 11 whichwhen exposed to flame .fiare upimmediatelytoset 1 1 0d theigniter. The burningof the igniter powder in turn 1 ignites :theends :ofa plurality 1 of1fuse trains 24 which: 1 1

1 branch outfrorn the ignitersand extend through the en- 1 tire massof1powder 2 1. 11 The-length and burning rate of 1 explosion takes place. 11 1 1 exhaust tube 25 of the plane, the exhaust being connected 1 in theusual manner. to, the combustion chamber of. the

engine. The; cartridges are ejected from a magazine or: 1 1 z-mechanical dispenser 26 down ai'chute .271 which leads 1: 1 1 1 intothe exhaust. The rate at which. the cartridges are 1 dropped: into theexhaust flame can; be incorporated, into 1 cartridges may beaccomplished by means of a time-con- 1 I to 11dcpend11upon: the speedofthe, vehicle, its altitude In lieu of a dispenser for the cartridges,

'a belt conveyer may be employed to drop the cartridges into theexhaust.

When the cartridge drops into the exhaust, the hairs '23 catch fire inthe flame, setting oh the igniter 22 and igniting the ends of fusetrains 24. At the same time, the cartridge receives rearward propulsionfrom the gases in the exhaust. The cartridge is hurled with great forceto a distance rearward of the vehicle and thereafter the flash powder isexploded to illuminate the terrain. The position of the cartridge at theinstant of explosion is sufliciently rearward to produce long shadows inthe photographs of military ground installations.

While there has been shown what is considered to be j a preferredembodiment of the invention, it will be mani- .25. the fusesshould besuch that the cartridgewill be at: the 1 1 desired distance intherear ofthe planebefore thefiash 1 1 1 1 1 i 1 The, cartridges 19 are fedatregulatcd intervals into the 1 I i 11 301 1 the cartridge dispensingmcchanism, 1 The release of the: 1 1 1 1 1 trolled mechanismsynchronizedwith the standard camera 1 1 1 intervalometer 2.7. 1 Therateof cartridge release is made 1 I 1 I 1 1 1 and theamount of overlapdesired in the 1strip of1aerial1 1 photographs.

fuse means ignitedby said exhaust to produce a delayed 1 explosioneffecting response of 2 said :electronic1 control 1 11 1 system tooperate said shutter; 1 1 1 1 1 1 1 1 1 1 1 1 I -31 An aerialphotographic system for a jetor rocket 1 plane having an exhaust tube,'said system comprising a 1 1 1 1 camera positioned in the fuselage ofthe 1 plane and 1 1 1 1 oriented to photograph the terrainbene'ath theplane, said 1 camera 1 including a shutter mechanism and aninter- 1 1valometer, acartridge dispenser containing a plurality of 1 1 1.ifiashpowder cartridges :and means to release sa'me into 1 saidexhaust, said: cartridges each having fusen1eans'ig 11 1 1 nited by saidexhaust to cause an explosion at: a point 1 1 1 1 1 rearwardlyof theplane, and. means coupling: said dis- 1 1 penser to' said intervalometerto "regulate the release of 11 1 1 said cartridges. 1 1 1 1 1 1 1 1 1 4;In ajetor rocket propelled missile provided with 1 1 1 rear exhausttubes'through which propulsive gases are 1 1 11 emitted, an aerial 1photographic system comprising a 1 1 camera having an exposure shutter,meansto drop a hash powder cartridge: into said exhaust to 1 causerearward 1 1 propulsion thereof, said cartridgehaving fuse means ig- 1 i1 nited by: said gases to cfiect an explosion thereof ata pointsufiiciently. rearward of the missle toproduce long shadows, and meansresponsive to the illumination of i said flash powder to actuate saidshutter, said illumination response means including a photocell orientedto inter cept light radiation from the explosion, an amplifier coupledto said photocell, and an electromagnetic device coupled to the outputof the amplifier and linked to said shutter to actuate same.

References Cited in the file of this patent UNITED STATES PATENTS383,984 Pifiard June 5, 1888 1,754,987 Driggs et a1. Apr. 15, 19301,936,595 Goddard Nov. 28, 1933 2,381,130 Lloyd Aug. 7, 1945 2,399,476Doyle et al. Apr. 30, 1946 2,714,999 Thieblotet a1. Aug. 9, 1955 FOREIGNPATENTS 1 i 486,946 Italy .......Nov. 19, 1955

